Carton opening tool



1954 T. MAYNARD CARTON OPENING TOOL Filed Oct. 13, 1953 VERTICAL SIDE suns-Ace OR OR IZONTAL TOP 50!? FACE QF CARTON [nveflfor TODD MAYNARD g dw u 027% United States Patent 2,695,447 Patented Nov. 30, 1954 CARTON OPENING TOOL Todd .Maynard, Chicago, Ill.

Application October 13, 1953, Serial No. 385,740

8 Claims. (Cl. 30-2) This invention relates to carton opening tools, and particularly to such tools wherein the cutting element is shielded or guarded when the tool is not in use.

In carton opening tools, it is common to have a handle with a guide plate fixed to the handle for engagement with and movement along one bordering surface of the corner of a carton, and to have a cutting blade spaced from this guide plate and rigidly related thereto so that this cutting blade will cut through the other bordering surface along such corner as the tool is drawn along the corner of the carton. Such prior cutting tools have, in some instances, been provided with spring type guards in an effort to avoid accidental cutting of the operator or others. In such prior tools, however, it has been found that the usefulness of the tools has been limited to a large extent by reason of the construction of such tools so that they can be used only in what may be termed a right-hand cutting operation, and since the particular user may find it more convenient to operate the tool with his left hand, to to operate it selectively in either a right-hand or left-hand manner, it is the primary object of the present invention to afford such a carton opening tool that may be readily used in either left-hand or right-hand cutting operations. A further and related object of the present invention is to afford such a carton opening tool that may be utilized for either right-hand or left-hand cutting operations and which has a knife guard means which is effective in either right-hand or left-hand operation of the tool.

Other and related objects of the present invention are to afford such a carton opening tool wherein the knife element has oppositely directed cutting edges that are symmetrically related to the operating handle of the tool, as well as to the mounting means whereby the cutting element is mounted in position on the handle,

and to so mount the cutting element on the handle that,

it may quickly and easily be reversed, thereby to enable both cutting edges of the blade to be utilized to their fullest extent, even though the use of the tool may be predominantly right-hand or left-hand, as the case may Another object is to afford a carton opening tool of the aforesaid character, wherein the sharpening replacement or reversing operations with respect to the blade may be performed quickly and easily and without a need for tools. 7

Other and further objects of the present invention are to afford a carton opening tool that is simple in form and which is effective and convenient in use.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show a preferred embodiment of the present invention and the principle thereof and what I now consider to be the best mode in which I have contemplated applying that principle. ther embodiments of the invention embodying the same or equivalent principle may be used and structural changes may be made as desired by those skilled in the art with out departing from the present invention and the purview of flre appended claims.

In the drawings:

Fig, l is a fragmentary perspective view illustrating a carton opening tool embodying the features of the invention and in use in a right-hand cutting operation along a top surface of a carton;

Fig. 2 is an extended perspective view illustrating the elllements of the cutting tool in a disassembled relation- 5 P;

Fig. 3 is a fragmentary side elevational view of the carton opening. tool with the shiftable guard in its normal or centered relationship;

Figs. 4 and 5 are similar views showing the tool in use in right-hand and left-hand cutting operations respectively; and

Fig. 6 is a sectional view taken subtantially along the line 6-6 of Fig. 4.

For purposes of disclosure, the invention is herein illustrated as embodied in a carton opening tool that has an elongated handle formed by stamping from heavy sheet metal to afford a body plate 21. This body plate 21 has formed handle plates 22 on opposite sides of its upper portion and held thereto by means such as rivets 23, so as to afford rounded easily held handle surfaces, and at its lower end, the body plate 21 has an enlarged guide plate 24 that is' symmetrical with the longitudinal axis of the body plate and which has its edges flared as at 24F to aid in guiding the tool in use as will be described hereinafter. Centrally of the enlarged guide plate 24, and on the longitudinal axis of the handle portion, a mounting stud 25 is afforded to serve as a supporting means for a double edged segmental cutting blade 26 and a swingable segmental guard 27, which is normally held in an effective centered position by means of a spring 28 so that both of the oppositely directed cutting edges 26C of the blade 26 are shielded and protected.

The cutting blade 26 is spaced from and parallel to the guide plate 24 so that when the side face of the guide plate 24 is engaged with one bordering surface along the corner of a carton, the blade 26 will be disposed in a plane parallel to such side face and in a position such that by application of cutting pressure, the cutting corher of the blade 26 may be forced downwardly and into cutting relationship with respect to the other bordering surface of the carton along such corner, and, as will be described in greater detail hereinafter, the guard 27 engages the surface of the carton that is being cut and is thus shifted or rocked to an out of the way position with respect to the cutting edge of the blade 26 that is to be effective. A comparison of Figs. 4 and 5 of the drawings illustrates clearly that the carton opening tool 20 of the present invention may be readily used. in either right-hand or left-hand cutting operations, and the operation is identical in each instance, except that the guard swings in the opposite direction and opposite cutting edges 26C of the blade are employed.

In attaining the advantageous operation that has thus been described, the present tool is constructed in such a manner that it may be economically manufactured and may be readily assembled and disassembled, as re quired, for replacement or reversal of the cutting blade, or for replacement of other parts such as the spring which constitutes an element that may be subject to breakage in the event of rough or long continued usage of the tool. Thus, in affording the desired convenience and simplicity of manufacture and assembly and disassembly, the mounting stud 25 and its relationship to the other elements of the tool are quite important. The mounting stud 25, as herein shown, has an enlarged head 25H that affords a shoulder 30 facing longitudinally of the stud. Adjacent the annular shoulder 30, an annular concentric bearing surface 31 is provided, and at the end of the annular bearing surface 31, the stud is reduced in diameter so as to afford a second annular shoulder 32 facing endwise away from the head 25H. Beyond the annular shoulder 32, the stud is generally cylindrical in form, with the exception however that it has one flat side 33 formed thereon which serves as a key for retaining certain parts of the structure in a nonrotative relationship which will be described. At its end, the stud 25 is screw threaded as at 34 so that it may receive a nut such as a wing nut 35 for holding the parts in assembled relationship.

In the assembly of the tool, the guard 2-7 is arranged to be mounted in what maybe termed a rockable relationship on the annular bearing surface 31 of the stud, and for purposes that will hereinafter become apparent, this rocking movement is limited so that the guard 27 has a limited rocking lost motion with respect to the stud 25. Such a mounting on the stud 25 is effected by providing an annular bearing opening 27B in the guard 27, this bearing opening 27B in its general form being complemental to the bearing surface 31, and this bearing opening 27 has a segmental extension 27E on one side thereof so that a pin 25P carried on the head 25H and projecting for a short distance longitudinally from the shoulder 30 will extend into the segmental extension 27E. Thus, in rocking movement of the guard 27 about the bearing surface 31, opposite ends of the segmental extension 27E will alternately engage the pin 25F to limit the rocking movement of the guard 27.

The guard 27 is, in the present case, formed from relatively thin sheet metal, and about all of its cdges it is provided with a flange 27F which projects toward the blade 26 and aids in the attainment of the desired protecting or guarding function. Midway between the opposite side edges of the guard 27, the guard is provided with an inwardly struck loop 27L that is utilized in affording an anchor for one arm 28-1 of the spring 28.

The spring 28 is in the form of a torsion spring, the coil of which is disposed about the bearing surface 31 of the stud 25, as shown in particular in Fig. 6 of the drawings, and, as hereinabove pointed out, one arm 28-1 of the torsion spring 28 extends through the anchoring loop 27L, while the other arm 28-2 has a laterally projecting finger 128 formed thereon by bending so that it may project through a slot 265 that is formed in the cutting blade 26 midway between the cutting edges thereof. The arms 28-1 and 28-2 are thus anchored to the guard 27 and the blade 26 respectively, and the normal relationship of these arms is such as to urge the guard to the centered effective relation of Fig. 3 wherein the blade 26 is fully concealed and protected.

The cutting blade 26 is segmental in form and its oppositely directed cutting edges 26C are preferably formed with an included angle therebetween of approximately 60 degrees, and at the narrow or central portion of the segmental cutting blade 26, a mounting opening 26M is provided which is complemental to the cross sectional form of the stud 25 in that portion of the stud that has the flat surface 33 thereon. The blade 26 is thus arranged so that it may be moved onto the flattened portion of the stud into engagement with the shoulder 32, and the stud 25 may then be put in position on the guide plate 24. In attaining the desired spacing of the cutting blade 26 with respect to the guide plate 24, spacing means are afforded about the stud 25, and such spacing means are, in the present instance, illustrated as being separately formed by a spacer sleeve 37 that is slipped onto the stud after the cutting blade 26 is in place thereon. The stud 25 is then extended through a D-shaped opening 38 that is formed in the guide plate 24, this D-shaped opening being complemental to the end portion of the stud so as to thereby hold the stud 25 against rotation and maintain the parts in the desired relationship. The stud 25 is held in place by the wing nut 35, which is tightened on the projecting end of the stud 25 so as to clamp the parts rigidly in the desired relationship.

With the structure that has thus been described, the tool may be used in an identical manner in either right-hand or left-hand operation, and in either type of operation, the guard 27 is shifted automatically to its retracted positron, as Wlll be evident in Figs. 1, 4 and of the drawings. It will be recalled that the cutting surfaces or edges 26C of the blade 26 are arranged so that the included angle therebetween substantially 60 degrees, and hence with the blade 26 mounted in a symmetrical relation with respect to the longitudinal axis of the handle 21, the cutting edges 26 are each displaced from such longitudinal axis at an angle of substantially 30 degrees. This particular angular relationship of the cutting edges with respect to the axis of the handle affords somewhat of a limitation upon the depth of cut that is normally attained with the present tool, slnce it will be evident that when the tool is grasped and moved along the corner of a carton, the angle of the tool as a whole with respect to the carton is limited by engagement of the fingers of the user with the surface of the carton in one direction, while if the handle is tilted upwardly at too great an angle, the desired cutting action Wlll not be attained, the cutting edge of the blade in such an mstance being disposed at an inefficient or i fictive 4 angle, which may be said to be too close to a perpendicular relationship with respect to the surface of the carton.

While the angle of the blade serves as aforesaid to limit to some extent the depth of cut that may be attained, it will be evident that a final or maximum limit for such depth of cut is afiorded by the stop means 25P-27E that are effective to limit the rocking or retracting movement of the guard 27. Such guard, after it has reached the limit of its rocking movement, serves as a positive depth of cut limiting means.

It will be evident that the present carton opening tool may be quickly and easily disassembled for sharpening, replacement, or reversal of the cutting blade 26, and because this work does not require the use of tools, such disassembly may be readily accomplished in those places Where tools of this character are ordinarily used.

From the foregoing description, it will be evident that the present invention affords a carton opening tool that is extremely simple in character, and which is capable of use in the different ways that may be required. More specifically, the present tool may be used for either right-hand or left-hand operation, as circumstances may require, and the operation in either mode of use is identical. Furthermore, the repair and upkeep of the present tool may be readily and easily accomplished on the job.

It will also be evident that the present tool provides a fully guarded relationship for the cutting tool, and that the guard means are capable of being automatically retracted in either direction as required by the mode of use of the tool. It will also be apparent that with the present tool, the depth of cut that may be attained is limited so that the present tool may be rapidly and effectively used without danger of damage to the contents of the carton.

Thus, while I have illustrated and described the preferred embodiment of my invention, it is to be understood that this is capable of variation and modification, and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the followin claims.

I claim:

l. A carton opening tool of the character described, comprising an elongated handle having a relatively flat guide plate disposed in fixed relation on said handle and symmetrical with relation to the longitudinal axis of the handle, a segmental cutting blade mounted in spaced parallel relation to said guide plate and with its cutting edges disposed in symmetrical relationship with respect to the longitudinal axis of said handle, a segmental guard plate mounted for rocking movement selectively in either direction from a normal centered guarding relation to expose one or the other of the cutting edges of said cutting blade, and stop means effective to" limit such rocking movement of said guard to thereby limit the depth of cut.

that may be effected with such blade.

2. A carton opening tool of the character described, comprising an elongated handle having a relatively flat guide plate disposed in fixed relation on said handle and symmetrical with relation to the longitudinal axis of the handle, a segmental cutting blade mounted in spaced parallel relation to said guide plate and with its diverging cutting edges having an included angle of substantially 60 degrees therebetween and being disposed in symmetrical relationship with respect to the longitudinal axis of said handle, and a segmental guard plate mounted for rocking movement selectively in either direction from a normal blade protecting relation to expose one or the other of the cutting edges of said cutting blade.

3. A carton opening tool of the character described, comprising an elongated handle having a relatively fiat guide plate disposed in fixed relation on said handle and symmetrical with relation to the longitudinal axis of the handle, a segmental cutting blade mounted in spaced parallel relation to said guide plate and with its cutting edges disposed in symmetrical relationship with respect to the longitudinal axis of said handle, a segmental guard mounted for rocking movement selectively in either direction to expose one or the other of the cutting edges of said cutting blade, spring means urging said guard to a normal centered relation wherein said blade is fully covered and protected, and stop means effective to limit such rocking movement of said guard to thereby limit the depth of cut.

that may be effected with such blade.

4. A. carton opening tool of the character described, comprising an elongated handle having a relatively flat guide plate disposed in fixed relation at one end thereof, a cutting blade mounted in spaced parallel relation to said guide plate, a guard plate mounted for rocking movement from a normal position to a retracted position to expose the cutting edge of said cutting blade, and stop means effective to limit such rocking movement of said guard to thereby limit the depth of cut that may be effected with such blade.

5. In a carton opening tool, an elongated body plate having an elongated upper handle portion adapted to be grasped in the hand of the user, and an integral lower guide plate symmetrical with the longitudinal axis of the handle, a mounting stud disposed normally to said guide plate on said axis of said handle and fixed nonrotatably with respect to said guide plate, a segmental cutting blade having oppositely directed diverging cutting edges and mounted on said stud spaced from and 'parallel to said guide plate and disposed with said cutting edges symmetrically related to and on opposite sides of a plane passing through the handle axis and the stud axis, a symmetrical guard somewhat larger than said segmental blade and mounted on said stud for rocking movement about the stud axis and disposed parallel to and in relatively closely spaced relationship with respect to said knife, and on the side of the knife that is remote from said guide plate, and a torsion spring having a torsion coil disposed about said stud between said knife and said guard and having opposite arms interlocked with said blade and guard respectively, said arms being so related as to normally position said guide in an overlying and protecting relation with respect to both cutting edges of the blade.

6. In a carton opening tool, an elongated body plate having an elongated upper handle portion adapted to be grasped in the hand of the user, and an integral lower guide plate symmetrical with the longitudinal axis of the handle, a mounting stud disposed normally to said guide plate on said axis of said handle and fixed non-rotataoly with respect to said guide plate, a segmental cutting blade having oppositely directed diverging cutting edges and mounted on said stud spaced from and parallel "to said guide plate and disposed with said cutting edges symmetrically related to and on opposite sides of a plane passing through the handle axis and the stud axis, a symmetrical guard somewhat larger than said segmental blade and mounted on said stud for rocking movement about the stud axis and disposed parallel to and in relatively closely spaced relationship with respect to said knife, and on the side of the knife that is remote from said guide plate, and spring means acting between said stud and said knife to normally position said guide in an overlying and protecting relation with respect to both cutting edges of the blade.

7. In a carton opening tool, an elongated. handle adapted to be grasped in the hand of the user and a rigid guide plate fixed on one end of said handle symmetrical with the longitudinal axis of the handle, a mounting stud disposed normally to said guide plate on said axis of said handle and fixed non-rotatably with respect to said guide plate, a segmental cutting blade having oppositely directed diverging cutting edges and mounted on said stud spaced from and parallel to said guide plate and disposed with said cutting edges symmetrically related to and on opposite sides of a plane passing through the handle axis and the stud axis, a symmetrical guard somewhat larger than said segmental blade and mounted on said stud for rocking movement about the stud axis and disposed parallel to and in relatively closely spaced relationship with respect to said knife, and on the side of the knife that is remote from said guide plate, a torsion spring having a torsion coil disposed about said stud between said knife and said guard and having opposite arms interlocked with said blade and guard respectively, said arms being so related as to normally position said guide in an overlying and protecting relation with respect to both. cutting edges of the blade, and stop means effective to limit rocking movement of said guard and thereby limit: the depth of cut.

8. In a carton opening tool, an elongated body plate having an elongated handle adapted to be grasped in the hand of the user and a rigid lower guide plate on said handle symmetrical with the longitudinal axis of the handle, a mounting stud disposed normally to said guide plate on said axis of said handle and fixed non-rotatably with respect to said guide plate, a segmental cutting blade having oppositely directed diverging cutting edges and mounted on said stud spaced from and parallel to said guide plate and disposed with said cutting edges symmetrically related to and on opposite sides of a plane passing through the handle axis and the stud axis, a symmetrical guard somewhat larger than said segmental blade and mounted on said stud for rocking movement about the stud axis and disposed parallel to and in relatively closely spaced relationship with respect to said knife, and on the side of the knife that is remote from said guide plate, spring means eifective to normally position said guide in an overlying and protecting relation with respect to both cutting edges of the blade, and means for limiting the rocking movement of said guard to thereby prevent unduly deep cutting by said blade.

No references cited. 

